[PATCH 3.10 14/35] perf/x86/amd: Rework AMD PMU init code

From: Greg Kroah-Hartman
Date: Fri Aug 14 2015 - 13:46:55 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

commit 1b45adcd9a503428e6de6b39bc6892d86c9c1d41 upstream.

Josh reported that his QEMU is a bad hardware emulator and trips a
WARN in the AMD PMU init code. He requested the WARN be turned into a
pr_err() or similar.

While there, rework the code a little.

Reported-by: Josh Boyer <jwboyer@xxxxxxxxxx>
Acked-by: Robert Richter <rric@xxxxxxxxxx>
Acked-by: Jacob Shin <jacob.shin@xxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20130521110537.GG26912@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/kernel/cpu/perf_event_amd.c | 34 +++++++++++++++++-----------------
1 file changed, 17 insertions(+), 17 deletions(-)

--- a/arch/x86/kernel/cpu/perf_event_amd.c
+++ b/arch/x86/kernel/cpu/perf_event_amd.c
@@ -648,48 +648,48 @@ static __initconst const struct x86_pmu
.cpu_dead = amd_pmu_cpu_dead,
};

-static int setup_event_constraints(void)
+static int __init amd_core_pmu_init(void)
{
- if (boot_cpu_data.x86 == 0x15)
+ if (!cpu_has_perfctr_core)
+ return 0;
+
+ switch (boot_cpu_data.x86) {
+ case 0x15:
+ pr_cont("Fam15h ");
x86_pmu.get_event_constraints = amd_get_event_constraints_f15h;
- return 0;
-}
+ break;

-static int setup_perfctr_core(void)
-{
- if (!cpu_has_perfctr_core) {
- WARN(x86_pmu.get_event_constraints == amd_get_event_constraints_f15h,
- KERN_ERR "Odd, counter constraints enabled but no core perfctrs detected!");
+ default:
+ pr_err("core perfctr but no constraints; unknown hardware!\n");
return -ENODEV;
}

- WARN(x86_pmu.get_event_constraints == amd_get_event_constraints,
- KERN_ERR "hw perf events core counters need constraints handler!");
-
/*
* If core performance counter extensions exists, we must use
* MSR_F15H_PERF_CTL/MSR_F15H_PERF_CTR msrs. See also
- * x86_pmu_addr_offset().
+ * amd_pmu_addr_offset().
*/
x86_pmu.eventsel = MSR_F15H_PERF_CTL;
x86_pmu.perfctr = MSR_F15H_PERF_CTR;
x86_pmu.num_counters = AMD64_NUM_COUNTERS_CORE;

- printk(KERN_INFO "perf: AMD core performance counters detected\n");
-
+ pr_cont("core perfctr, ");
return 0;
}

__init int amd_pmu_init(void)
{
+ int ret;
+
/* Performance-monitoring supported from K7 and later: */
if (boot_cpu_data.x86 < 6)
return -ENODEV;

x86_pmu = amd_pmu;

- setup_event_constraints();
- setup_perfctr_core();
+ ret = amd_core_pmu_init();
+ if (ret)
+ return ret;

/* Events are common for all AMDs */
memcpy(hw_cache_event_ids, amd_hw_cache_event_ids,


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